Background: Infantile cardiomyopathy is a genetically heterogeneous disorder with significant morbidity and mortality.
Methods: This study aimed to identify the mutation present in four unrelated patients who presented as infants with isolated hypertrophic cardiomyopathy.
Results: In all four, a novel mitochondrial m.8528T→C mutation was identified. This results in a change of the initiation codon in ATPase 6 to threonine and a concurrent change from a highly conserved hydrophobic amino acid, tryptophan, at position 55 of ATPase 8 to a highly basic arginine. To our knowledge, this is the first report of a mutation affecting both mitochondrial genome-encoded complex V subunit proteins. Testing of the relatives of one patient indicated that the mutation is heteroplasmic and correlated with disease.
Conclusion: Mitochondrial genome sequencing should be considered in patients with infantile hypertrophic cardiomyopathy.
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▸ A supplementary table is published online only at http://jmg.bmj.com/content/vol46/issue5
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Funding: This study was supported by grants from the Children’s Cardiomyopathy Foundation to SMW and a National Institutes of Health award (5R01 CA100023) to LJW.
Competing interests: None.
Patient consent: Parental consent obtained.